The present invention relates to cooling of electrical and electronic components, and more particularly, to a cold plate utilizing fin configurations with an evaporating refrigerant to cool electrical and electronic components.
Electrical and electronic components (e.g. microprocessors, IGBT""s, power semiconductors etc.) generate heat which must be removed for reliable operation and long life of the components. One method of removing this heat is to mount the component on a cold plate, which is in turn cooled by a fluid flowing through it. Cold plates use a liquid flowing through tubes or offset strip fins or convoluted fins to remove heat from a surface where electrical or electronic components are mounted. The liquid flowing through the cold plate removes heat by an increase in its sensible temperature, with no phase change being involved. The tube or fins are in thermal contact with a flat surface where the components are mounted by means of screws, bolts or clips. A thermal interface material is usually employed to reduce the contact resistance between the component and the cold plate surface. There are many types of cold plate designs, some of which involve machined grooves instead of tubing to carry the fluid. However, all cold plate designs operate similarly by using the sensible heating of the fluid to remove heat. The heated fluid then flows to a remotely located air-cooled coil where ambient air cools the fluid before it returns to the pump and begins the cycle again.
Modern electrical and electronic components are required to dissipate larger quantities of heat at ever increasing heat flux densities. It is therefore very difficult to cool these components by sensible cooling only. For every watt of heat dissipated, the cooling fluid must increase in temperature; or if the temperature rise is fixed, the flow rate of fluid must increase. This causes either large fluid flow rates, or large temperature differences, or both. As fluid flow rate increases, pumping power goes up, as does this size of pumps required. This can cause unacceptable parasitic power consumption, equipment packaging difficulties, and even erosion of cold plate passages due to high fluid velocities. As the temperature rise of the cooling fluid increases, sometimes the allowable temperature of the device or component may be exceeded, causing premature failure.
It is seen then that there exists a continuing need for an improved method of removing heat from a surface where electrical or electronic components are mounted, particularly with the dissipation of larger quantities of heat at ever increasing heat flux densities being required.
This need is met by the present invention, which uses fin in multiple configurations, constructed as a part of a cold plate. The fin can be a high surface area offset strip fin, a plain convoluted fin, or other fin configurations. The cold plate of the present invention uses a vaporizable refrigerant as the fluid medium, passing through the fin configuration, to efficiently remove heat from components or devices mounted on the surface of the cold plate.
In accordance with one aspect of the present invention, an improved cold plate cooling system provides cooling away from the surface of electrical and electronic components with very low parasitic power consumption and very high heat transfer rates. The component to be cooled is in thermal contact with a cold plate. A fin material is inserted in the cold plate and refrigerant is circulated through the fin, allowing the cold plate and fin to transfer heat from the electrical or electronic components, as the liquid refrigerant is at least partially evaporated by the heat generated by the components.
Accordingly, it is an object of the present invention to provide cooling to electrical and electronic components. It is a further object of the present invention to provide cooling across large surface areas. It is yet another object of the present invention to provide nearly isothermal cooling to electrical and electronic components.